edu.uci.ics.jung.algorithms.shortestpath

Class UnweightedShortestPath<V,E>

java.lang.Object

edu.uci.ics.jung.algorithms.shortestpath.UnweightedShortestPath<V,E>

All Implemented Interfaces:

Distance<V>, ShortestPath<V,E>

public class UnweightedShortestPath<V,E>
extends Object
implements ShortestPath<V,E>, Distance<V>

Computes the shortest path distances for graphs whose edges are not weighted (using BFS).

Author:

Scott White

Constructor Summary

Constructors

Constructor and Description
UnweightedShortestPath(Hypergraph<V,E> g) Constructs and initializes algorithm

Method Summary

Modifier and Type	Method and Description
Number	getDistance(V source, V target) Returns the distance from the source vertex to the target vertex.
Map<V,Number>	getDistanceMap(V source) Returns a Map which maps each vertex in the graph (including the source vertex) to its distance (represented as a Number) from source.
Map<V,E>	getIncomingEdgeMap(V source) Returns a map from vertices to the last edge on the shortest path to that vertex starting from source.
void	reset() Clears all stored distances for this instance.
void	reset(V v) Clears all stored distances for the specified source vertex source.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

UnweightedShortestPath

public UnweightedShortestPath(Hypergraph<V,E> g)

Constructs and initializes algorithm

Parameters:

g - the graph

Method Detail

getDistance

public Number getDistance(V source,
                          V target)

Description copied from interface: Distance

Returns the distance from the source vertex to the target vertex. If target is not reachable from source, returns null.

Specified by:

getDistance in interface Distance<V>

Parameters:

source - the vertex from which distance is to be measured

target - the vertex to which distance is to be measured

Returns:

the distance from source to target

See Also:

Distance.getDistance(Object, Object)

getDistanceMap

public Map<V,Number> getDistanceMap(V source)

Description copied from interface: Distance

Returns a Map which maps each vertex in the graph (including the source vertex) to its distance (represented as a Number) from source. If any vertex is not reachable from source, no distance is stored for that vertex.

Specified by:

getDistanceMap in interface Distance<V>

Parameters:

source - the vertex from which distances are to be measured

Returns:

a Map of the distances from source to other vertices in the graph

See Also:

Distance.getDistanceMap(Object)

getIncomingEdgeMap

public Map<V,E> getIncomingEdgeMap(V source)

Description copied from interface: ShortestPath

Returns a map from vertices to the last edge on the shortest path to that vertex starting from source.

Specified by:

getIncomingEdgeMap in interface ShortestPath<V,E>

Parameters:

source - the starting point for the shortest paths

Returns:

a map from vertices to the last edge on the shortest path to that vertex starting from source

See Also:

ShortestPath.getIncomingEdgeMap(Object)

reset

public void reset()

Clears all stored distances for this instance. Should be called whenever the graph is modified (edge weights changed or edges added/removed). If the user knows that some currently calculated distances are unaffected by a change, reset(V) may be appropriate instead.

See Also:

reset(Object)

reset

public void reset(V v)

Clears all stored distances for the specified source vertex source. Should be called whenever the stored distances from this vertex are invalidated by changes to the graph.

Parameters:

v - the vertex for which distances should be cleared

See Also:

reset()